The present invention relates to the installation of underground pipelines, conduits, cables, and the like, and more particularly to installation using directional drilling, which is sometimes referred to as horizontal boring. More particularly, the invention relates to a reamer for use in enlarging a pilot bore in a method of horizontal drilling and a method of using the reamer in horizontal drilling.
U.S. Pat. No. 5,314,267 issued on May 24, 1994 to Mark Osadchuk, discloses a horizontal pipeline boring apparatus and method for installing a pipeline section under a surface barrier, such as a roadway or the like. According to that invention, a pilot bore is formed under the barrier. Next, a boring head, which is sometimes referred to in the art as a reamer or a hole opener, is used to enlarge the pilot bore. In addition, a guide is positioned on the advancing side of the boring head. The guide on the boring head is designed to engage the walls of the pilot bore and help steer the pipeline boring head during cutting along the path of the pilot bore. The pipeline section is advanced behind the boring head. Drilling liquids can be supplied to the boring operation through the pilot bore, and an auger in the pipeline section is used to help move drilling mud and cuttings away from the boring head through the pipeline section. U.S. Pat. No. 5,314,267 is hereby incorporated by reference in its entirety.
U.S. Pat. No. 5,979,573 issued Nov. 9, 1999 discloses a boring head for use in mounting to a drill pipe of a drilling rig for enlarging a pilot bore in horizontal boring operations. The boring head has an axial member positioned along a central axis of the boring head for connecting the boring head to the drill pipe of the drilling rig. A plurality of flanges extend radially from the axial member, and a flange support frame is provided for structurally interconnecting and supporting the flanges on the axial member. A plurality of cutting cones are mounted to the boring head. In particular, each of the cutting cones has a cone axis; each of the cutting cones is mounted to one of the flanges such that its cone axis extends at an acute angle ranging from zero degrees up to about 45 degrees relative to the central axis; each of the cutting cones is mounted for independent rotation about its cone axis; and each of the cutting cones has a plurality of independently-rotatable cutting bits mounted thereto. According to a further aspect of the invention, the cutting cones are arranged and positioned on the boring head to improve the cutting operation. U.S. Pat. No. 5,979,573 is hereby incorporated by reference in its entirety.
U.S. Pat. No. 5,979,574 issued Nov. 9, 1999 discloses a boring head provided for use in mounting to a drill pipe of a drilling rig for enlarging a pilot bore in horizontal boring operations. The boring head has an axial member positioned along a central axis of the boring head for connecting the boring head to the drill pipe of the drilling rig. A plurality of internally-tapered longitudinal pockets around the periphery of the axial member each receive an externally-tapered body mounting an independently-rotatable cutter bit which rotates about a rolling axis inclined at an angle in the range between ten degrees and eighty degrees with respect to the central axis of the boring head. The tapered body is drawn into the tapered pocket by a threaded retainer and forced into the pocket when boring by the force of the boring head against the bore face. U.S. Pat. No. 5,979,574 is hereby incorporated by reference in its entirety. (If there is any conflict between the usage or definition of a term in a patent incorporated by reference and the usage herein, the usage or definition herein will control.)